Dutch Rainwater Composition 1992-2011

Data

Data is in a number of spreadsheets. The script is a variation on last week, with an extra wrapper for spreadsheets. The final parts are merging locations (Station Leiduin and Witteveen have been replaced by De Zilk and Valthermond respectively) and adding the equipment variable. The code is at the bottom of the post.

pH

It seems pH is still slightly increasing. It also seems there are like two levels of pH. For instance, in Gilze-Rijen the pH is either around 5 or around 6. But 5.5 is less probable.

Iron

For Iron there are just four locations with complete data. Hence these are displayed. It would seem the trend downward continues.

Iron model

Since I wanted to give the two machines each a separate variance, I opted to use nlme in this particular calculation. In addition, rather than following the plot, all locations are used, and the replacement stations are not merged together. The machines seem to give similar variation, which probably means variation in iron concentration is much larger than machine accuracy. The decrease estimate is still around 5% per year.

Wiekvoet

Wiekvoet is about R, JAGS, STAN, and any data I have interest in. Topics range from sensometrics, statistics, chemometrics and biostatistics. For comments or suggestions please email me at wiekvoet at xs4all dot nl.